Biblical numerology, the study of the significance of numbers in the Bible, is an interesting consideration. Certainly there is a relationship between numbers and events connected with them in the Bible, but we must be careful not to take this too far. It reminds me of the danger of types. We recognize the existence of types in the Scriptures, but some would take typology too far and find types where none occur. Perhaps I will at a later time deal with Biblical numerology in greater detail.
Concerning your specific question about the number 40, it is indeed often used in the Bible in connection with tribulation or trial. You gave a few examples in your question. Also, Israel wandered 40 years in the wilderness. Hebrews 3:8 and 9 read: “Harden not your hearts, as in the provocation, in the day of temptation in the wilderness: when your fathers tempted me, proved, me, and saw my works forty years.”
The apostle Paul stated concerning his persecution: “Of the Jews five times received I forty stripes save one” (2 Cor. 11:24).
I would be cautious about saying that 40 always signifies trial or tribulation. You might like to look up “forty” in a concordance, and judge for yourself!
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